TY - CONF A1 - Beck, Uwe A1 - Lange, Thorid A1 - Hielscher, Stefan A1 - Rietz, Uwe A1 - Lerche, D. A1 - Pfuch, A. T1 - Multiple-sample approach for bonding and testing: validation of bonding strength of adhesive-bonded joints and adhesive tapes N2 - The multiple-sample approach by means of centrifugal adhesion testing (CAT-technology) allows the determination of bonding strength of adhesive-bonded joints on a statistical basis of up to eight samples. Therefore, it is obvious to ensure the continuous handling and identical processing of an octet of samples within the entire process chain of wet-chemical cleaning, plasma-chemical pre-treatment, bonding of samples, and testing of bonding strength. Within the multiple-sample bonding set-up (MPKV-technology) a defined bonding pressure can be adjusted regardless the actual number of samples. A comparison of single- and multiple-sample approach is made for bonding strength of selected adhesives, double-sided adhesive tapes and different material combinations [stainless steel (V2A) vs. stainless steel, polyamide (PA), or polypropylene (PP)]. It is shown that both technologies improve reliability of results T2 - EURADH 2016 Adhesion ´16 CY - Glasgow, UK DA - 21.09.2016 KW - Multiple-sample bonding KW - Multiple-sample testing KW - Bonding strength KW - Adhesives and adhesive tapes PY - 2016 SP - 162 EP - 166 AN - OPUS4-37588 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Beck, Uwe A1 - Baier, Jennifa A1 - Hidde, Gundula A1 - Hielscher, Stefan A1 - Kittler-Packmor, Kai A1 - Lange, Thorid A1 - Mix, Renate A1 - Weise, Matthias T1 - Multiple-sample approach: reliable ranking and validated statistics of bonding and adhesive strength N2 - Bonding strength of adhesive-bonded joints and adhesive strength of coatings have been exclusively determined in single-sample tests using a tensile testing machine. Necessarily, the single-sample approach was also applied to the corresponding bonding procedure. As a consequence, reliability and reproducibility of results were restricted. By applying the newly introduced centrifuge technology, the multiple-sample approach was realized for simultaneous tensile testing of up to eight samples under identical conditions without any disturbing shear-force effects. In order to introduce the multiple-sample approach into the bonding procedure, a hydraulic bonding set-up was developed which enables identical bonding pressure also for slightly different heights of sample assemblies. Both sample approaches were compared for various application examples: ranking of different classes of adhesives, validated statistics of adhesive-bonded joints using one particular adhesive and effects of cleaning and plasma-treatment on the adhesive strength of coatings. The investigated systems included glass, metals and polymer substrates, different adhesives, metallic and dielectric coatings on polymers. KW - Bonding strength KW - Adhesive strength KW - Multi-sample approach KW - Centrifuge technology PY - 2014 SN - 978-3-944261-28-7 SN - 978-3-944261-36-2 SN - 978-3-944261-52-2 VL - 5 SP - 1 EP - 5 AN - OPUS4-31310 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rietz, U. A1 - Lerche, D. A1 - Beck, Uwe A1 - Hielscher, Stefan A1 - Kern, Janine T1 - Determination of bonding, adhesive and composite strength by means of centrifuge technology N2 - The quality and durability of bonded joints, coated systems and composites depend on various factors. Therefore effective quantitative tests to determine adhesive, bonding or composite strength are of great need for R&D and QC. In this paper a new measuring principle is described which uses the centrifugal force to generate the test load. By the geometry of the whole measurement set-up, the test specimen are supported from only one side, the influence of shear forces is avoided. The possibility to test up to eight samples in one measurement under identical testing conditions allows a high sample throughput. A detailed description of the whole sample preparation procedure including pre-treatment is followed by the specification of the measuring protocol as well as result analysis. For each application area bonding strength of joints, adhesive strength of coated systems and internal strength of composite materials examples are presented. T2 - EURADH 2014 - 10th European Adhesion Conference CY - Alicante, Spain DA - 22.04.2014 KW - Adhesive strength KW - Bonding strength KW - Composites KW - Centrifuge technology KW - Zentrifugentechnologie KW - Klebfestigkeit KW - Haftfestigkeit KW - Mehr-Proben-Prüfen/Kleben PY - 2014 SN - 978-84-616-9067-1 SN - 84-616-9067-2 SP - Paper 47, 203 EP - 206 AN - OPUS4-31311 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Beck, Uwe A1 - Baier, Jennifa A1 - Hidde, Gundula A1 - Hielscher, Stefan A1 - Kittler-Packmor, Kai A1 - Lange, Thorid A1 - Mix, Renate A1 - Weise, Matthias T1 - Multiple-sample approach: reliable ranking and validated statistics of bonding and adhesive strength N2 - Bonding strength of adhesive-bonded joints and adhesive strength of coatings have been exclusively determined in single-sample tests using a tensile testing machine. Necessarily, the single-sample approach was also applied to the corresponding bonding procedure. As a consequence, reliability and reproducibility of results were restricted. By applying the newly introduced centrifuge technology, the multiple-sample approach was realized for simultaneous tensile testing of up to eight samples under identical conditions without any disturbing shear-force effects. In order to introduce the multiple-sample approach into the bonding procedure, a hydraulic bonding set-up was developed which enables identical bonding pressure also for slightly different heights of sample assemblies. Both sample approaches were compared for various application examples: ranking of different classes of adhesives, validated statistics of adhesive-bonded joints using one particular adhesive and effects of cleaning and plasma-treatment on the adhesive strength of coatings. The investigated systems included glass, metals and polymer substrates, different adhesives, metallic and dielectric coatings on polymers. T2 - EURADH 2014 - 10th European Adhesion Conference CY - Alicante, Spain DA - 22.04.2014 KW - Bonding strength KW - Adhesive strength KW - Multi-sample approach KW - Centrifuge technology PY - 2014 SN - 978-84-616-9067-1 SN - 84-616-9067-2 SP - Paper 49, 211 EP - 214 AN - OPUS4-31309 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Beck, Uwe A1 - Reiners, Georg A1 - Lerche, D. A1 - Rietz, U. A1 - Niederwald, H. T1 - Quantitative adhesion testing of optical coatings by means of centrifuge technology N2 - Although adhesion testing of coatings is of fundamental interest for quality assurance, it is still a challenge regarding reliable quantitative results. Because of the huge variety of coating/ substrate systems in terms of materials and thickness range, adhesion tests display the same variety as coating/substrate systems. Some tests are qualitative, many are quantitative but except for the pull (DIN EN ISO 15870) and pull-off test (DIN EN ISO 4624) adhesion is not measured in terms of force per area. For optical coatings, the standardized tests according to ISO 9211-4 apply, i.e. abrasion tests (cheese cloth or eraser test) and adhesion tests (tape or cross-hatch test) with different degrees of severity. Instead of the adhesion strength, all these single-sample tests provide only quantitative information on the abrasion or adhesion resistance of a particular coating/ substrate system. The centrifuge test has manifold advantages. First, it can be easily run as multiple-sample test. Second, adhesion strength is measured in absolute numbers (N/mm2). Third, the centrifuge test requires only a one-sided sample support instead of a two-sided sample clamping as the pull- and pull-off test do. Fourth, it is much easier and faster than many other tests. Fifth, the centrifuge technology additionally enables tests under defined climates or harsh environments. Last but not least, versatile test conditions (alternating loads at various load rates) important to fatigue testing can be easily realized by varying the number of revolutions. The centrifuge test was applied to the testing of optical coatings on glass and CaF2. It could be shown that there are significant advantages compared to other tests. In particular, the centrifuge test was able to discriminate the adhesion strength for coating/substrate systems until failure which all passed the standardized tests of ISO 9211-4. KW - Adhesion strength KW - Bonding strength KW - Optical coatings KW - Pull-off test KW - Centrifuge test KW - Quantitative adhesion testing PY - 2011 U6 - https://doi.org/10.1016/j.surfcoat.2011.02.016 SN - 0257-8972 VL - 205 IS - Supplement 2 SP - S182 EP - S186 PB - Elsevier Science CY - Lausanne AN - OPUS4-23285 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rietz, U. A1 - Lerche, D. A1 - Hielscher, Stefan A1 - Beck, Uwe T1 - Centrifugal adhesion testing technology (CATT) - A valuable tool for strength determination N2 - A new technology for strength determination of adhesive-bonded joints based on analytical centrifugatioon is introduced. Tensile as well as shear strength can be measured for multiple test specimens simultaneously within a very short time. The experimental procedure is described from sample preparation, application of adhesives, sample mounting within the centrifuge to testing parameters and sequences. All requirements of DIN EN 15870 are fulfilled and, in addition, a higher throughput and a better reproducibility can be obtained. The experimental results are discussed regarding bonding strength development over time, comparison of tensile and shear strength and various testing conditions. Furthermore, an additional application field of centrifuge technology is described with respect to the determination of the adhesive strength of coatings. The novel centrifuge based technology provides the determination of bonding, adhesive and shear strength on a statistical basis under identical testing conditions for up to eight samples. Moreover, sophisticated two-sided sample clamping, necessary for a tensile testing machine, is replaced by a simple plug-in procedure. KW - Centrifuge technology KW - Adhesive strength KW - Interface strength KW - Bonding strength KW - Adhesion KW - Tensile strength KW - Shear strength KW - Centrifuge KW - Multiple sample testing PY - 2015 SN - 0916-4812 SN - 0001-8201 VL - 51 IS - S1 (Special Issue on WCARP-V) SP - 293 EP - 297 PB - Kyokai CY - Osaka AN - OPUS4-33994 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hielscher-Bofinger, Stefan A1 - Beck, Uwe A1 - Lerche, D. A1 - Rietz, U. T1 - Multiple-sample Testing: Adhesive Strength of Coatings and Bonding Strength of Adhesives evaluated by Centrifugal Adhesion Testing (CAT) N2 - The quantitative determination of adhesion and cohesion properties is a key requirement for adhesive-bonded joints and coated components in both R&D and Quality assurance. Because of the huge variety of layer/substrate Systems in terms of materials and large thickness range, adhesion tests display the same diversity as layer/substrate systems. There are only two tensile testing procedures available, that determine adhesive strength in terms of force per area (N/mm²), the single-sample pull-off test in a tensile testing machine and the multiple-sample-test using the Centrifugal Adhesion Testing (CAT) Technology. The CAT Technology is a testing method which uses centrifugal force as tensile testing force in a multiple-sample arrangement within a drum rotor of a Desktop centrifuge. Hence, the adhesive/bonding strength A/B can be determined on a statistical basis under identical testing conditions for up to eight samples. A variety of examples for bonding strength of adhesives, adhesive strength of coatings and compound strength of composite materials is discussed such as metalto-metal and glass-to-metal bonding, sputtered SiO2-layers on CR39 Polymer and carbon fiber reinforced polymer. T2 - Colloquium Department 6. CY - Berlin, BAM, Germany DA - 03.09.2020 KW - Centrifugal Adhesion Testing (CAT) KW - Adhesive strength KW - Bonding strength KW - Composite strength KW - Interlaboratory comparision PY - 2020 AN - OPUS4-51178 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Beck, Uwe A1 - Hidde, Gundula A1 - Lange, Thorid A1 - Gargouri, H. A1 - Kärkkänen, I. A1 - Naumann, F. T1 - Plasma Activation and Plasma-assisted ALD Surface Modification of Polymers for Improved Bonding and Adhesive Strength N2 - Bonding strength is crucial on polymers of low surface energy, for clean surfaces limited to 0.5, 1, and 2 MPa for PTFE, PP, and PE. Plasma treatment may improve bonding strength by a factor of 2 (PTFE) or 5 (PP and PE). The efficiency of treatment is usually 10% as both low pressure and atmospheric pressure processes show low topographic conformity. Besides, lifetime of activation/modification is rather short. Hence, bonding has to be carried out immediately after plasma treatment. The concept of plasma-assisted ALD (atomic layer deposition) interlayers was introduced in the project HARFE of SENTECH (modification/deposition/in-situ monitoring) and BAM (bonding, characterization, testing). ALD deposition has a high surface conformity and for dielectric films of Al2O3 also a good long-term stability given that the films are dense enough. Based on TMA and O2/O3 precursors, ALD layer stacks from 60 to 375 monolayers were prepared under different conditions. For a transfer time of 24 hours from deposition to measurement, bonding strength could be increased up to 5 MPa (PTFE) respectively 10 MPa (PP, PE). The huge potential of ALD layers as adhesive interlayers was demonstrated for Al2O3 on stainless steel with bonding strength beyond 15 MPa, i.e. interface strength within the ALD stack is also in this range. This is a prerequisite for subsequent PVD/CVD-deposition in hybrid systems. By means of the SI ALD LL system of SENTECH thermal and plasma-supported ALD processes can be alternatively realized. Ellipsometric in-situ monitoring provides monolayer sensitivity and reveals that the efficient bonding of the lower ALD layers on the polymer has to be further improved. Testing of bonding strength was realized by CAT (centrifugal adhesion testing) technology. It was shown that ALD modification correlates with the increase of surface energy and bonding strength. T2 - PSE 2018 - 16th Conference on Plasma Surface Engineering CY - Garmisch-Partenkirchen, Germany DA - 17.09.2018 KW - Plasma activation KW - Plasma-assisted ALD modification KW - Adhesive ALD interlayer KW - Bonding strength KW - Adhesive strength PY - 2018 AN - OPUS4-46015 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Beck, Uwe A1 - Hielscher, Stefan A1 - Lange, Thorid A1 - Rietz, U. A1 - Lerche, D. T1 - State-of-the-Art in Multiple-Sample Evaluation of Adhesive and Bonding Strength N2 - The paper addresses the “State-of-the-Art in Multiple-Sample Evaluation of Adhesive and Bonding Strength” and the following points are discussed in more detail: 1. Motivation (coatings, varnishes, tapes, laminates, CFRP, adhesive-bonded joints) 2. Conventional single-sample testing (evaluation of adhesive and bonding strength; failure pattern) 3. Multiple-sample handling (MSH), bonding (MSB), and testing: centrifugal adhesion testing (CAT) (multiple-sample approach, tensile test within a centrifuge) 4. Application examples of CAT-Technology™ (laminates, optical coatings, CFRP joints) Finally, a summary is given regarding status quo and benefits of CAT-technology under tensile stress conditions whereas examples of testing in a centrifuge under compressive stress conditions are mentioned in the outlook. T2 - The 5th International Conference Competitive Materials and Technology Processes CY - Miskolc-Lillafüred, Hungary DA - 08.10.2018 KW - Centrifugal Adhesion Testing KW - CAT KW - Multiple-sample handling (MSH) KW - Multiple-sample bonding (MSB) KW - Tensile strength of laminates KW - Tensile strength of coatings KW - Adhesive strength KW - Bonding strength PY - 2018 AN - OPUS4-46336 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -